The invention relates to amphiphilic, non-ionic oligoesters that are free-flowing at an ambient temperature. Said oligoesters are produced by reacting dicarboxylic acid compounds, polyol compounds of water-soluble alkylene oxide addition products and optionally diol compounds. The invention also relates to detergent formulations and concentrates containing the aforementioned oligoesters and the use of oligoesters as additives in detergents, in particular for cleaning hard surfaces.